A number of technology applications require the creation of precise relief structures having critical dimensions from the multi-micron to the nanometer size regime. Roll-to-roll (R2R) processes for reproducing such structures often utilize a patterning tool in the form of a cylinder or belt, and a number of methods for producing cylindrical tools are well known to the art, particularly in the graphic arts field. Typically such tools comprise one or more discrete pattern elements attached to the outer surface of a support member. See U.S. Pat. Nos. 5,147,763; 6,163,523; 4,836,874; and 4,486,363. Examples of seamed tools used in R2R optical disc fabrication include those disclosed in W. D. Slafer, M. Kime, and R. Monen, “Continuous Web Manufacturing of Thin-Coverslip Optical Media”, SPIE Optical Data Storage '92, San Jose, Calif., 12 Feb. 1992.
The seams that can result from forming patterning tools from discrete elements often represent a limitation in manufacturing processes that utilize such tools. Even in cases in which the pattern to be replicated is already composed of discrete elements (such as discs, cards, display screens, etc.), the seams can effect the production process, such as by causing “speed bumps” at the seam which cause pressure roller bouncing (especially at higher line speeds), trapping of processing fluid in low spots, “tenting” at high spots (resulting in non-contact between the substrate and the tool pattern), etc. Seams can also result in performance and visual limitations in the material being produced by such tools, for example in diffractive optical elements, large-area displays, embossed holographic foils and the like.
Because the creation of cylindrical patterning tools can be expensive and time consuming, particularly when a very precise and/or finely-detailed pattern is involved, it is very desirable to be able to quickly and inexpensively make precise replicas of such tools.